Traditionally, contact lens production processes include each lens being formed by sandwiching monomer or monomer mixture between a front curve (lower) mold section and back curve (upper) mold section. The monomer is polymerized, thus forming a lens which is then removed from the mold sections and either packaged dry or further treated in a hydration bath and packaged for consumer use.
Recent developments in the hydration and automated handling of wet contact lenses, as taught in U.S. Pat. No. 5,476,111, entitled “Automated Method and Apparatus for Hydrating Soft Contact Lenses” has enabled automatic robotic handling of lenses during hydration, and prior to the inspection thereof by the automated lens inspection system. Additionally, a number of automated systems have been designed to transport a hydrated lens from a lens hydration pallet or bath to the primary package in which it will be sterilized, stored, and delivered to a consuming patient. Traditionally, the automated lens transfer apparatus includes a number of transfer elements including suckers configured to create a lens retaining vacuum which is used to maintain the lens on the sucker during lens transfer to a primary package. Typically, a traditional primary package will include a preformed polypropylene member or boat that will receive and contain the contact lens and a specified quantity of packaging saline. During the traditional packaging process, the boat is charged with a measured quantity of saline to which is added the polymerized contact lens. Once the lens and saline are placed within the boat, the package is closed by heat sealing a laminated foil to the top of the package.
However, traditional systems and methods for transferring hydrated contact lenses to a primary package have suffered from a number of shortcomings. Specifically, transferring an at least partially hydrated lens from a lens hydration bath to a primary package often resulted in the lens inverting, slipping, sliding, or otherwise moving on the sucker apparatus. Consequently, the subsequent placement of the lens into the primary package is less than ideal. In particular, when the precise placement of the lens into the primary package is critical, traditional systems are not adequate. Consequently, traditional lens transfer is typically performed manually or with a dry lens.
An additional shortcoming of traditional lens transfer systems and methods is that once a lens is securely located on the sucker transfer apparatus, surface tension between the lens and the sucker transfer apparatus will assist in maintaining the lens on the transfer apparatus. However, successful removal of the lens from the sucker transfer apparatus has to completely overcome that surface tension. Consequently, traditional systems often eject a blast of air and/or fluid from the sucker transfer apparatus to remove the lens. Often, partial retention of the lens occurs due to the presence of surface tension between the lens and a portion of the sucker transfer apparatus. Alternatively, if sufficient air and/or fluid are forced upon the lens to remove the lens from the sucker transfer apparatus, there is a potential for damage to the lens.